A simple model for peer-to-peer video-on-demand system in broadcast environment

In order to provide a cost effective and scalable solution for a large-scale VoD system, a number of system topologies and transmission protocols have been proposed in the literature in the past decade, such as proxy caching, content delivery network (CDN), peer-to-peer (P2P), multicast and periodic broadcast. However, these approaches have their own problems for video delivery. To compensate their disadvantages, in this paper, we develop a hybrid VoD system model that uses a P2P paradigm coupled with video broadcasting and CDN-like approach for video delivery. In the proposed architecture, the video is first partitioned into two parts. The first part of the video is transmitted among customers, watching the video, in P2P manner while the second part of the video is broadcasted periodically by the central server. This content delivery strategy allows the workload of the system disperse over the network while customers can still guarantee to obtain the service without collapsing by the dynamic nature of P2P framework. In addition, it also takes a benefit from video broadcasting. Analytical model is developed to allow system designers better understanding of system dynamics and provide guidelines for the management of design resources and realization of VoD services based on this architecture.